the semi-colon denotes a line end. It is not nessasary, but it looks nice.
FMRES_*'s denote what to tell MetaMod about the forward return type. IGNOR E means continue on past, HANDLE means stop here, SUPERCEDE means this return value and operation goes above all others, OVERRIDE means to override the value.
Look it up in the documentation before asking here; it saves time and effort.